This invention relates to a numerical control method and, more particularly, to a numerical control method for executing numerically controlled machining along a projected path obtained by projecting a programmed path, lying on a predetermined plane, onto a plane of projection inclined at a predetermined angle with respect to the first-mentioned plane.
In machine tools, especially wire-cut electric discharge machines, there are cases where cutting is performed along a path obtained by projecting a programmed path lying on a predetermined plane, such as the X-Y plane, on a plane of projection which is inclined at a predetermined angle (projection angle) with respect to the X-Y plane. The path obtained is referred to as a projected path. In some instances a path such as a circular arc on the X-Y plane will not be a circular arc when projected on the plane of projection. It has therefore been conventional practice to create numerical control (NC) data specifying the projected path and then execute numerical control processing on the basis of this data in order to perform cutting along the projected path. The conventional method is disadvantageous, however, in that creating the NC data specifying the projected path requires considerable programming time and is a troublesome task.